Improvement in step-ladders



c. FmzELL. Step-Ladders. No. 140,359. Patenredlulymsvs.

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l l l UNITED STATES PATENT OFFICE.

CHARLES FRIZELL, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN STEP-LADDERS.

Specification forming part of Letters Patent No. 140,359, dated July 1, 1873 application filed April 10, 1873.

T o all whom it may concern:

Be it known that I, CHARLES FRIZELL, of Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Step-Ladders, of which the following is a specification This invention relates to that class of ladders Which are formed with dat steps instead of rungs, and which are usually made seltsupporting by means of a hinged support at the back; and the invention consists in constructing the side or string pieces each of two parts or bars, placed parallel or nearly so to each other, and connected by rungs or bars, while lateral braces are inserted in such bars and connected with the steps. The sides or string pieces are also strengthened by a metallic tie, the ends of which are secured to the upper string-piece of the sides, while it is carried under one or more ofthe central steps, in order the better to economize its tensional strength, for the support ot' the side or string piece.

ends, and serve the purposes ot' symmetry, uniting the exposed ends of the bars and affording a broader bearing for the sides. d d are the lateral braces, the lower ends ot' which are secured in ties b, While the upper ends are secured in steps c. ff are metallic truss-rods, the ends of which are secured to the upper bar aby screws g, as shown in Figs. l and 2, while the rod is carried under the central step, as shown in Fig. 2, thereby producing the desired deection of the rod to insure a tensional strain upon it when the weight upon the ladder is nea-r the center. Fig. 3 represents the back support, which is hinged to the ladder, as shown in Figs. 2 and 3 5 but, as no claim is made thereto, a more definite description is not deemed necessary.

I desire to state brieliy the advantages of my invention, which are lightness, great strength, durability, rigidity, and resistance to lateral and indirect pressure, with great economy in 'material required for its construction.

That I claim as my invention is- 1. rThe sides A, when constructed with bars a ct and tie-rods b, substantially as and for the purposes specified.

2. rThe combination and arrangement of tierods b, braces d, and steps c, substantially in manner as and for the purposes specied.

CHARLES FRIZELL.

Witnesses:

EBEN HUToHlNsoN, T. W. PORTER. 

